1. Field of the Invention
The present invention relates to an ultrasonic treatment apparatus which grasps a treated target between a treatment section to which an ultrasonic vibration is transmitted and a jaw openable and closable relative to the treatment section, so as to treat the grasped treated target by use of the ultrasonic vibration.
2. Description of the Related Art
For example, U.S. Patent Application Publication No. 2012/0310264 discloses an ultrasonic treatment apparatus which includes a treatment section to which an ultrasonic vibration is transmitted and a jaw openable and closable relative to the treatment section. In this ultrasonic treatment apparatus, when vibration generating electric power is transmitted from an electric power source to a vibration generating section, the ultrasonic vibration is generated in an ultrasonic transducer which is the vibration generating section. Then, the generated ultrasonic vibration is transmitted to the treatment section, and the treatment section treats a treated target such as a biological tissue by use of the transmitted ultrasonic vibration. Here, opening and closing directions of the jaw are perpendicular (transverse) to a transmitting direction of the ultrasonic vibration. When the ultrasonic vibration is transmitted to the treatment section in a state where the treated target is grasped between the treatment section and the jaw, frictional heat is generated between the treated target and the treatment section. By the frictional heat, the treated target is coagulated and simultaneously incised. Furthermore, in the ultrasonic treatment apparatus, an ultrasonic impedance value of the vibration generating electric power is detected with time, and it is judged whether the ultrasonic impedance value is within a range of a first default threshold or more and a second default threshold or less, the second threshold being greater than the first threshold.